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Depositional Environment of the Sangkarewang Oil Shale, Ombilin Basin, Indonesia Anggayana, Komang; Widayat, Agus Haris; Widodo, Sri
Journal of Engineering and Technological Sciences Vol 46, No 4 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Five samples from 56 m long drill core of lacustrine Sangkarewang oil shale have been studied by means of petrography and organic geochemistry to investigate the organic matter composition and depositional environments of the shale. The organic matter consists of abundant lamalginite (30%, v/v) and very limited amount of vitrinite, suggesting aquatic depositional environments with minor terrestrial influence. Organic geochemical analysis exhibits the dominance of pristane, phytane, and generally n-alkanes compounds. These compounds might originate mostly from aquatic photosynthetic organisms. The oil shale was likely deposited in anoxic lake environments, suggested by the presence of framboidal pyrite (6%, v/v) and preserved organic matter with total organic carbon (TOC) about 4.9%. The pristane/phytane ratio is relatively high about 3.9 and thought as source sensitive rather than redox sensitive. Hopanoid and aryl isoprenoid compounds are present in minor amounts. The latter compounds are interpreted to be derived from green sulfur bacteria dwelling in anoxic and the presence of H2S in bottom water.

Exhumation and Tectonomagmatic Processes of the Granitoid Rocks from Sulawesi, Indonesia: Constrain from Petrochemistry and Geothermobarometry Study Maulana, Adi; Imai, Akira; Watanabe, Koichiro; van Leeuwen, Theo; Widodo, Sri; Musri, Musri
Indonesian Journal on Geoscience Vol 6, No 2 (2019)
Publisher : Geological Agency

DOI:10.17014/ijog.6.2.153-174Exhumation and tectonomagmatic processes of the granitoid from Sulawesi were discussed using petrochemistry (e.g. petrographic and major element compositions) and geothermobarometry data (mineral chemistry data). Detailed petrographic observations were conducted to determine the mineral composition, texture, and structure of the granitoid rocks, whereas the whole rock composition were determined using XRF method, and the mineral chemistry was analyzed using Electron Microprobe Analyzer (EPMA). The granitoids are classified as calc-alkaline, metaluminous I-type. Pressures of 0.91 to 1.2 kbar and emplacement depths of 3.2 to 4.3 km at temperatures of 677 - 729Â°C were estimated for Mamasa Pluton. Whereas Masamba Pluton was emplaced at pressures of 2.3 to 2.8 kbar, temperatures of 756 - 774Â°C, and emplacement depths of 8.2 to 10 km. Moreover, Lalos-Toli and Sony Plutons were emplaced at temperatures of 731 to 736Â°C and 601 to 609Â°C, respectively. The pressures varying from 3.1 to 3.3 kbar and 3.2 to 3.4 kbar, equate to an emplacement depth of 11.3 and 11.6 km, respectively. Gorontalo Pluton emplaced at temperatures of 662 - 668Â°C with the pressure range from 2.6 to 2.7 kbar, is equivalent to 9.3 km deep. Varied oxidation state (ranging from -14 to 19) is inferred from the mineral assemblages, showing a strong association with highly oxidized I-type series granitic rocks. The exhumation rate estimation shows that Mamasa and Masamba Plutons were exhumed respectively at a rate of 0.37 and 1.6 mm/year, whereas Lalos-Toli and Sony Plutons at 1.4 and 2.7 mm/year, respectively. Gorontalo Pluton located in the Northern Sulawesi Province was exhumed at 0.42 mm/year. The rapid exhumation rate of Sony Pluton is attributed to the active vertical movement of Palu-Koro Fault Zone which has been active since Pliocene. It shows that faulting may play an important role in differential exhumation of intrusive bodies in the orogenic belt.

Exhumation and Tectonomagmatic Processes of the Granitoid Rocks from Sulawesi, Indonesia: Constrain from Petrochemistry and Geothermobarometry Study Maulana, Adi; Imai, Akira; Watanabe, Koichiro; van Leeuwen, Theo; Widodo, Sri; Musri, Musri
Indonesian Journal on Geoscience Vol 6, No 2 (2019)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.6.2.153-174

DOI:10.17014/ijog.6.2.153-174Exhumation and tectonomagmatic processes of the granitoid from Sulawesi were discussed using petrochemistry (e.g. petrographic and major element compositions) and geothermobarometry data (mineral chemistry data). Detailed petrographic observations were conducted to determine the mineral composition, texture, and structure of the granitoid rocks, whereas the whole rock composition were determined using XRF method, and the mineral chemistry was analyzed using Electron Microprobe Analyzer (EPMA). The granitoids are classified as calc-alkaline, metaluminous I-type. Pressures of 0.91 to 1.2 kbar and emplacement depths of 3.2 to 4.3 km at temperatures of 677 - 729Â°C were estimated for Mamasa Pluton. Whereas Masamba Pluton was emplaced at pressures of 2.3 to 2.8 kbar, temperatures of 756 - 774Â°C, and emplacement depths of 8.2 to 10 km. Moreover, Lalos-Toli and Sony Plutons were emplaced at temperatures of 731 to 736Â°C and 601 to 609Â°C, respectively. The pressures varying from 3.1 to 3.3 kbar and 3.2 to 3.4 kbar, equate to an emplacement depth of 11.3 and 11.6 km, respectively. Gorontalo Pluton emplaced at temperatures of 662 - 668Â°C with the pressure range from 2.6 to 2.7 kbar, is equivalent to 9.3 km deep. Varied oxidation state (ranging from -14 to 19) is inferred from the mineral assemblages, showing a strong association with highly oxidized I-type series granitic rocks. The exhumation rate estimation shows that Mamasa and Masamba Plutons were exhumed respectively at a rate of 0.37 and 1.6 mm/year, whereas Lalos-Toli and Sony Plutons at 1.4 and 2.7 mm/year, respectively. Gorontalo Pluton located in the Northern Sulawesi Province was exhumed at 0.42 mm/year. The rapid exhumation rate of Sony Pluton is attributed to the active vertical movement of Palu-Koro Fault Zone which has been active since Pliocene. It shows that faulting may play an important role in differential exhumation of intrusive bodies in the orogenic belt.

Depositional Environment of the Sangkarewang Oil Shale, Ombilin Basin, Indonesia Komang Anggayana; Agus Haris Widayat; Sri Widodo
Journal of Engineering and Technological Sciences Vol. 46 No. 4 (2014)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2014.46.4.6

Five samples from 56 m long drill core of lacustrine Sangkarewang oil shale have been studied by means of petrography and organic geochemistry to investigate the organic matter composition and depositional environments of the shale. The organic matter consists of abundant lamalginite (30%, v/v) and very limited amount of vitrinite, suggesting aquatic depositional environments with minor terrestrial influence. Organic geochemical analysis exhibits the dominance of pristane, phytane, and generally n-alkanes compounds. These compounds might originate mostly from aquatic photosynthetic organisms. The oil shale was likely deposited in anoxic lake environments, suggested by the presence of framboidal pyrite (6%, v/v) and preserved organic matter with total organic carbon (TOC) about 4.9%. The pristane/phytane ratio is relatively high about 3.9 and thought as source sensitive rather than redox sensitive. Hopanoid and aryl isoprenoid compounds are present in minor amounts. The latter compounds are interpreted to be derived from green sulfur bacteria dwelling in anoxic and the presence of H2S in bottom water.

Exhumation and Tectonomagmatic Processes of the Granitoid Rocks from Sulawesi, Indonesia: Constrain from Petrochemistry and Geothermobarometry Study Adi Maulana; Akira Imai; Koichiro Watanabe; Theo van Leeuwen; Sri Widodo; Musri Musri
Indonesian Journal on Geoscience Vol 6, No 2 (2019)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17014/ijog.6.2.153-174

DOI:10.17014/ijog.6.2.153-174Exhumation and tectonomagmatic processes of the granitoid from Sulawesi were discussed using petrochemistry (e.g. petrographic and major element compositions) and geothermobarometry data (mineral chemistry data). Detailed petrographic observations were conducted to determine the mineral composition, texture, and structure of the granitoid rocks, whereas the whole rock composition were determined using XRF method, and the mineral chemistry was analyzed using Electron Microprobe Analyzer (EPMA). The granitoids are classified as calc-alkaline, metaluminous I-type. Pressures of 0.91 to 1.2 kbar and emplacement depths of 3.2 to 4.3 km at temperatures of 677 - 729°C were estimated for Mamasa Pluton. Whereas Masamba Pluton was emplaced at pressures of 2.3 to 2.8 kbar, temperatures of 756 - 774°C, and emplacement depths of 8.2 to 10 km. Moreover, Lalos-Toli and Sony Plutons were emplaced at temperatures of 731 to 736°C and 601 to 609°C, respectively. The pressures varying from 3.1 to 3.3 kbar and 3.2 to 3.4 kbar, equate to an emplacement depth of 11.3 and 11.6 km, respectively. Gorontalo Pluton emplaced at temperatures of 662 - 668°C with the pressure range from 2.6 to 2.7 kbar, is equivalent to 9.3 km deep. Varied oxidation state (ranging from -14 to 19) is inferred from the mineral assemblages, showing a strong association with highly oxidized I-type series granitic rocks. The exhumation rate estimation shows that Mamasa and Masamba Plutons were exhumed respectively at a rate of 0.37 and 1.6 mm/year, whereas Lalos-Toli and Sony Plutons at 1.4 and 2.7 mm/year, respectively. Gorontalo Pluton located in the Northern Sulawesi Province was exhumed at 0.42 mm/year. The rapid exhumation rate of Sony Pluton is attributed to the active vertical movement of Palu-Koro Fault Zone which has been active since Pliocene. It shows that faulting may play an important role in differential exhumation of intrusive bodies in the orogenic belt.

Identifikasi Biomarker Fraksi Aromatik Batubara Muara Wahau, Kalimantan Timur 2016 Basuki Rahmad; Komang Anggayana; Sri Widodo; Agus Haris Widayat
Jurnal Ilmu Kebumian Teknologi Mineral (JIK TekMin) Vol 1, No 2 (2015)
Publisher : Fakultas Teknologi Mineral

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The research location in Wahau Muara District, East Kutai Regency, East Kalimantan Province. Geological setting of Muara Wahau located in the Kutai Basin Upper included in the Early Miocene Formations Wahau. Coal of Muara Wahau has a unique characteristic that inertinite abundant content with an average value of 20.1% with a low maturity (immature) with Rv (random) 0.40 to 0.44 including lignite rank.Coal samples taken from Seam-1 directly from drill core which drill hole GT-02. Intake of sample done by coring method with the preparation ply by ply based on lithotype appearance. Laboratory analysis of coal samples for organic geochemical analyzes conducted by Soxhlet extraction and then using column chromatography to obtain aromatic fractions.Picene derivatives such as 1,2,4a, 9-tetramethyl-1,2,3,4,4a, 5,6,14b-octahydropicene dominate with the highest concentration of 6509 mg / g TOC than other pentacyclic compounds in the aromatic hydrocarbon fraction Muara Wahau coal.The presence amyrin resulting from microbial degradation or the result of oxidative degradation in tropical climates and several derivatives amyrin typical of Muara Wahau coal one of which is a non-aromatic fraction hopanoid pentacyclic triterpenoids (picene) indicating Angiosperm plant origin. Picene presence implies that the formation of Muara Wahau coal still in the initial transformation during the first stage of diagenesis (early diagenetic) with the maturity level is low (immature). Keywords: picene; amyrin; oxidative degradation; tropis; angiosperm; immature. ABSTRAKLokasi penelitian terletak di Kecamatan Muara Wahau, Kabupaten Kutai Timur, Propinsi Kalimantan Timur. Tatanan geologi daerah Muara Wahau berada di Cekungan Kutai Bagian Atas termasuk dalam Formasi Wahau berumur Miosen Awal. Batubara Muara Wahau memiliki keunikan yang khas yaitu kandungan inertinite yang berlimpah dengan nilai rata-rata 20,1% dengan kematangan yang rendah (immature) dengan Rv (random) 0,40-0,44 termasuk peringkat lignite.Conto batubara diambil dari Seam-1 langsung dari inti bor yaitu lubang bor GT-02. Pengambilan conto dilakukan dengan metode coring dengan preparasi ply by ply berdasarkan kenampakan lithotype. Analisa laboratorium conto batubara untuk analisis geokimia organik dilakukan dengan cara ekstraksi soxhlet kemudian menggunakan column chromatography untuk memperoleh fraksi aromatik.Turunan picene seperti 1,2,4a,9-tetramethyl-1,2,3,4,4a,5,6,14b-octahydropicene mendominasi dengan konsentrasi paling tinggi 6509 µg/g TOC dibanding senyawa-senyawa pentasiklik lainnya dalam fraksi hidrokarbon aromatik batubara Muara Wahau.Kehadiran amyrin yang dihasilkan dari microbial degradation atau akibat dari oxidative degradation di iklim tropis dan beberapa turunan amyrin yang khas dari batubara Muara Wahau salah satunya adalah fraksi aromatik non-hopanoid pentacyclic triterpenoid (picene) yang mengindikasikan tumbuhan asal angiosperm. Kehadiran picene mengimplikasikan bahwa pembentukan batubara Muara Wahau masih dalam transformasi awal selama tahap pertama diagenesis (early diagenetic) dengan tingkat kematangan yang masih rendah (immature). Kata kunci: picene; amyrin; oxidative degradation; tropis; angiosperm; immature.

PENGARUH KOMPOSISI ASH BATUBARA TERHADAP KUALITAS KLINKER PORTLAND CEMENT PADA PT. SEMEN TONASA UNIT III Nurlianti Dahliar; Sri Widodo; Adi Tonggiroh
Jurnal Penelitian Geosains Vol. 10 No. 2 (2014)
Publisher : Jurnal Penelitian Geosains

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Portland cement clinker is a hydraulic material consists of C3S, C2S, C3A and C4AF. For producing clinker, raw meal have been burn in kiln at temperature 1450oC by using the heat combustion from coal. Clinker burning process is the most important process for the cement industry. In the portland cement industry, coal was not only used as a fuel, but it can also affected the composition of clinker. The coal ash will be mixed with raw meal during clinkerization process. Therefore, when the quality of the coal is not in accordance with the raw meal, it will cause crude clinker. The main purpose of study is to determine the influence of coal ash toward clinker quality. It should be known because portland cement clinker quality of PT. Semen Tonasa have to be on standard according to ASTM C-150-1999 and SNI No. 15-6514-2001. The results of paired T-test analysis showed that the composition of the coal ash which affected the quality of clinker after clinkerization process were LSF, SM, C3S, C2S, and C4AF. Based on the result of simple regression analysis, the amount of coal ash composition toward clinker portland cement quality was minor. LSF had the highest influence up to 0.885%, AM range between 0.1-0.3%, C2S range between 0.01-0.07%, C3S range between 0.01-0.02%, and C4AF was 0.019%.Keywords: clinker, coal ash, quality, C3S, C4AF, portland cement

Geochemical study of ultramafic rocks from Latowu area of North Kolaka, Southeast Sulawesi and its implication for CO2 sequestration S Sufriadin; Sri Widodo; Akane Ito; Tsubasa Otake; Kenzo Sanematsu
Journal of Degraded and Mining Lands Management Vol 5, No 4 (2018)
Publisher : Brawijaya University

Geochemistry of ultramafic rocks in the Latowu Area of North Kolaka Regency, Southeast Sulawesi has been investigated with the aim at deciphering of mineral characteristics, chemical composition and their potential use as carbon dioxide storage. Mineralogy was characterized by both scanning electron microscopy (SEM) and X-ray diffractometry (XRD); whereas bulk rock and mineral chemistry were analyzed by means of X-ray fluorescence spectrometry (XRF) and Electron probe microanalyzer (EPMA) respectively. Results of analyses show that lizardite is predominant serpentine mineral present, followed by chrysotile and trace amount of magnetite. Remnants of olivine and pyroxene were detected in some samples but they have been pseudomorphicly replaced by serpentine. Serpentinization of Latowu ultramafic rocks has led to decrease in grain size and density. Lizardite is characterized by fine grained particles with higher in iron. The higher Mg and Fe of the rocks indicate a suitability as feed materials for carbon dioxide sequestration. Mineral and chemical properties of ultramafic rocks have significant role in evaluating the feasibility of mineral carbonation.

Analisis Losses pada Pemindahan Material Lgso di Front Penambangan Bukit Hilux Menuju Stockyard Pelabuhan PT Antam UBPN Sultra Habibie Anwar; Sri Widodo; Muhammad Nur Alim; Emi Prasetyawati Umar; Dirgahayu Lantara; Arif Nurwaskito; Alam Budiman Thamsi
Jurnal Geomine Vol 7, No 3 (2019): Edisi Desember 2019
Publisher : Universitas Muslim Indonesia

Salah satu front penambangan yang dimiliki PT.ANTAM Tbk. UBPN SULTRA adalah Bukit Hilux. Kegiatan produksi penambangan di Bukit Hilux difokuskan pada penambangan material Low Grade Saprolith Ore (LGSO). Material LGSO adalah kelompok bijih nikel kadar rendah yang diperuntukkan untuk ekspor dengan batas kadar tertentu. Sebelum diekspor, hasil penambangan material LGSO ini diangkut menuju Stockyard Transito yang ditumpuk menjadi tumpukan Eksportable Transit Ore (ETO) kemudian dilakukan rechek sampel. Setelah hasil rechek sampel keluar, maka material LGSO tersebut diangkut menuju Stockyard Pelabuhan dan ditumpuk menjadi tumpukan Eksportable Final Ore (EFO) yang siap untuk diekspor. Adanya tahapan pemindahan material LGSO dari front penambangan Bukit Hilux hingga ke Stockyard Pelabuhan menyebabkan losses material. Penelitian ini dimaksudkan untuk menganalisis berapa persentase losses material LGSO tersebut dan penyebab terjadinya dengan melakukan perhitungan tonase menggunakan metode survey dan ritase alat angkut yang dikalibrasikan dengan data timbangan serta pengamatan kegiatan pemindahan. Adapun losses yang dihasilkan sebesar 2,17 % untuk pemindahan dari front menuju Stockyard Transito dan 1,33 % untuk pemindahan dari Stockyard Transito menuju Stockyard Pelabuhan. Penyebab terjadinya losses antara lain adanya material yang melekat pada alat berat dan faktor dumping yang membuat sebagian material menjadi landasan.

Identifikasi Clay Bands Pada Endapan Batubara Berdasarkan Data Well Logging Di Daerah Nunukan Provinsi Kalimantan Utara Muhammad Idris Juradi; Sri Widodo; Anshariah Anshariah; Alfian Nawir; Emi Prasetyawati Umar; Andi Fahdli Heriansyah; Agus A Budiman; Firdaus F; Alam Budiman Thamsi
Jurnal Geomine Vol 9, No 1 (2021): Edisi April 2021
Publisher : Universitas Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33536/jg.v9i1.812

Salah satu faktor yang mempengaruhi kualitas batubara adalah adanya keberadaan clay bands pada lapisan endapan batubara. Maksud dari penelitian ini adalah untuk memahami mekanisme kerja Well Logging dalam eksplorasi geofisika khususnya clay bands pada lapisan batubara sesuai dengan hasil well logging sedangkan tujuannya untuk mengetahui kedalaman dan ketebalan clay bands pada lapisan batubara sesuai dengan data log secara vertikal. Metode penelitian yang dilakukan adalah metode induktif yang menggunakan pendekatan kombinasi antara penelitian kualitatif dan kuantitatif, dengan memadukan hasil-hasil kajian pustaka, data lapangan yang keseluruhannya dikaji, dianalisis, dan disintesis secara komprehensif untuk menyimpulkan rangkaian penelitian yang telah dilakukan. Berdasarkan hasil penelitian yang dilakukan, didapatkan kedalaman (posisi) clay bands pada sumur logging PDH41 seam 1 dijumpai pada kedalaman 30,40 - 31,40 meter dengan ketebalan 1 meter, clay bands pada seam 2 dijumpai pada kedalaman 34,80 - 35,80 meter dengan ketebalan 1 meter, sumur logging PDH34 dijumpai clay bands pada kedalaman 71,20 - 71,80 meter dengan ketebalan 0,60 meter, sumur logging PDH37 dijumapi clay bands pada kedalaman 12,20 - 13,50 meter dengan ketebalan 1,3 meter. Dari 9 sumur logging 3 sumur diantaranya terdeteksi adanya clay bands sedangkan 6 sumur logging tidak terdeteksi adanya clay bands.

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